In recent years, an automatic processor called a mini-lab set up at a shop front for processing photographic materials has prevailed for a quick print service for general users and the rationalization of collection and delivery between a photograph shop and a processing laboratory. The development processing agents for use in mini-labs are in many cases supplied in the form of liquid composition comprising processing chemicals of the component dissolved in advance in a solvent, e.g., water, since this form is advantageous in that a processing solution can be easily prepared at the time of use by mixing and dilution with water. However, the form of liquid composition requires containers for containing the solvent, e.g., water, for dissolving processing components, i.e., processing chemicals, and for the composition, which is disadvantageous in the point of transfer costs. Therefore, liquid composition is generally supplied in the form of a concentrated liquid processing composition (called “concentrated” in place of “condensed” in the industry) to reduce the volume by concentration.
Further, a concentrated liquid processing composition in many cases consists of a plurality of composition units not as the constitution of a single solution from various reasons such as storage stability, degree of concentration and handleability. The composition units constituting a concentrated composition are called parts.
Describing as to color development processing composition, when processing composition is constituted by a plurality of parts, it is advantageous in the point that the stability of the composition is increased and further concentration and volume reduction are contrived, but it is accompanied by disadvantages such that a plurality of concentrated solutions must be mixed not a simple dilution with water in preparing a processing solution, and workload increases in disposing many empty containers of compositions. Accordingly, even if processing composition is composed of single constitution (hereinafter referred to as one-part constitution or one liquid type constitution, which are the same meaning), when storage stability is ensured and the composition is concentrated, facilities for usage are extremely high.
From the above viewpoint, concentrated composition: of one-part constitution for a color developer replenisher has been conventionally developed and introduced to the market in practice, but the concentrated composition of one-part constitution cannot sufficiently cope with the latest trend of needs in the market in the following points, and such is the state of things that concentrated processing composition of the plural part constitution is rather generally used.
As the problems of concentrated composition of one-part constitution for a color developer replenisher, in the first place, although further concentration has been required of the processing composition in recent years for the purpose of a quick print service for general users and for the reduction of discharge of a waste solution, the requirement is not sufficiently met; secondly, a phenomenon of precipitation of the components of a developing replenisher prepared from concentrated processing composition in a replenishing tank which is called creeping over, and the desensitization of a photographic material to be processed are not sufficiently solved; and thirdly, it is necessary to reduce the cost as the processing agent at least to the same with or lower than the cost of the processing agent of the plural part constitution.
With respect to the first problem, it is necessary to highly activate a color developing solution so as to shorten a developing process for a quick print service, it is necessary to reduce replenishing amount for the reduction of discharge of a waste solution, and it is necessary to supply processing chemicals necessary for development reaction by a reduced replenishing amount. At all events, further concentration of a color developer replenisher, i.e., further concentration of concentrated composition for a developer replenisher, becomes necessary.
However, compatibility of thickening and stabilization does not yet reach sufficient level in one liquid type development processing composition such that precipitation is liable to occur due to temperature fluctuation during storage when the concentration of development processing composition is increased. For example, a concentrated developing composition, of one-part constitution having carbonate concentration of from 0.5 to 2 mol/liter, a molar ratio of potassium ion to sodium ion of from 1 to 4, and pH of 12.5 or more is disclosed in JP-A-11-194462 (the term “JP-A” as used herein means an “unexamined published Japanese patent application”). The concentration of a developing agent can be made high by this developing composition, but higher concentration without generating precipitation is difficult, e.g., in a case where a replenishing amount is as low as 45 ml/m2 of a photographic material, or in a case of rapid development where color development processing time is 25 seconds.
Creeping over, which is the second problem, is a phenomenon that the components of a developing solution mainly comprising a developing agent and a fluorescent brightening agent creep up and generate precipitation in a developer replenisher tank, in particular over a part where a liquid is in contact with air on the tank wall, and the upper part of that part, or when a floating lid or a floating ball is used (they are used in general) for preventing oxidation of a replenisher, the upper part of such a floating lid or a floating ball. Further, desensitized development means a phenomenon that when the precipitated crystals crept over peel off, fall into a replenisher tank and are dissolved, the sensitivity of a photographic material processed with that replenisher lowers. A technique of solving these problems concerning concentrated composition of one-part constitution for a color developer replenisher has not yet found.
With respect to the third problem of the cost, e.g., concentrated developing composition of one-part constitution containing 0.06 mol/liter or more of a p-phenylenediamine color developing agent in a state of free base (not forming a salt), having pH of from 7 to 13, and containing a straight chain organic solvent having a molecular weight of from 50 to 200 having a hydroxyl group in the same amount with water or more is disclosed in U.S. Pat. No. 6,017,687. Although this composition is concentrated, an inexpensive salt type developing agent (e.g., sulfate) cannot be used as the color developing agent, or the removal of sulfate is necessary, so that this composition is not practicable in the point of cost.
Accordingly, processing composition for a color developer replenisher having high degree of concentration capable of answering development of further low replenishing rate and/or rapid development required in recent years, free of a creeping phenomenon in a replenisher tank, moreover, practicably low cost, does not yet reach the level of satisfying a strong demand of the market.